The present invention relates to a gas-insulated switchgear having gas sealed metal conduits each housing at least a main bus and components of switching devices which are connected thereto by lead buses branched from the main bus, and particularly, to an improvement thereof to reduce an installation area thereof and the number of other components thereof.
FIGS. 1 and 2 are a plan and side views of a conventional gas-insulated switchgear shown in, for example, Japanese Utility Model Application Laid-open No. 73113/1981, respectively, which is of a combined three-phase type and is composed of a pair of electric units 10. In these figures, a reference numeral 1 depicts main buses each including three different phase conductors. Each main bus 1 extends through a gas filled metal conduit 1a and is insulatingly supported thereby. The main buses 1 are parallel to each other, one of which is for an auxiliary purpose. A reference numeral 2 depicts lead buses each including three different phase conductors branched from each of the main buses 1, all of the lead conductors 2a the main buses 1 of each conduit 1a extending through a sealed metal conduit 2a. A reference numeral 3 depicts a pair of three-phase disconnecting switches connected to the respective lead concuctors 2, 4 a pair of vertically arranged commutators, 5 three-phase circuit breakers, 6 control devices of the gas-insulated switch device, 7 three-phase disconnecting switches, 8 sealed metal conduits enclosing junctions between terminals of the lead conductors 2 and cables 22 for external connection and 9 grounding means. The disconnecting switches 3 and 7, the commutators 4, the circuit breakers 5 and the grounding means 9 are associated with gas-sealed, rigid metal containers which are filled with insulating gas.
A plurarity of the units 10 each constructed as mentioned above are arranged side by side above two pairs of the three-phase main buses 1 which are orthogonal thereto. The sealed conduits 1a are connected by flexible joints 21 mutually,
FIGS. 3 and 4 are a plan and side views, respectively, of another example of the conventional gas-insulated which is of phase-separation type and is shown as including two three-phase units 20 each including three single phase main buses 11 arranged in a sealed metal conduit 11a. One of the units is for an auxiliary purpose. Lead buses 12 each including a lead conductor branched from the respective main buses 11 extend through metal conduits 12a and through metal conduits 12b and 12c. A pair of disconnecting switches 13 of phase-separation type are connected to the respective lead buses 12. A pair of vertically arranged commutators 14, circuit breakers 15 of phase-separation type, control devices 16 for the gas insulated electric unit, disconnecting switches 17 of phase-separation type, sealed metal containers 18 for enclosing joints between terminals of the lead buses 12 and cables 24 for external connection and grounding means 19 are also provided. The disconnecting switches 13 and 17, the commutators 14, the circuit breakers 15 and the grounding means 19 have frames each comprising a sealed metal container which is gas-filled.
The three-phase units 20 each composed of three single phase circuits are arranged above a pair of the parallel three-phase main buses each composed of three main buses 11, orthogonally thereto. Sealed metal conduits 11a for the main buses 11 of the units 20 are connected by flexible joints 23 to each other.
In the conventional gas-insulated device constructed as above, the installation area of the units increases proportionally to the number of the units, and the number of the main buses as well as their conduits has to be equal to the number of, the units. Further, the flexible joints 21 and 23 must be sufficient in number too.
U.S. Pat. No. 4,237,520 to Oishi et al discloses vertically arranged electric units. Since in this Patent the electric units have their elements arranged in straight-line fashion, the installation area thereof is not reduced sufficiently.